Yu Henry, Kutana Alex, Yakobson Boris I
Applied Physics Program, Rice University, Houston, Texas 7700, United States.
Materials Science & Nanoengineering, Rice University, Houston, Texas 77005, United States.
Nano Lett. 2022 Apr 13;22(7):2934-2940. doi: 10.1021/acs.nanolett.2c00103. Epub 2022 Mar 15.
Electron optics is the systematic use of electromagnetic (EM) fields to control electron motions. In graphene, strain induces pseudo-electromagnetic fields to guide electron motion. Here we demonstrate the use of substrate topography to impart desirable strain on graphene to induce static pseudo-EM fields. We derive the quasi-classical equation of motion for Dirac Fermions in a pseudo-EM field in graphene and establish the correspondence between the quasi-classical and quantum mechanical snake states. Based on the trajectory analysis, we design sculpted substrates to realize various "optical devices" such as a converging lens or a collimator, and further propose a setup to achieve valley Hall effect solely through substrate patterning, without any external fields, to be used in valleytronics applications. Finally, we discuss how the predicted strain/pseudo-EM field patterns can be experimentally sustained by typical substrates and generalized to other 2D materials.
电子光学是系统地利用电磁场（EM）来控制电子运动。在石墨烯中，应变会诱导赝电磁场来引导电子运动。在此，我们展示了利用衬底形貌在石墨烯上施加理想应变以诱导静态赝电磁场。我们推导了石墨烯中赝电磁场里狄拉克费米子的准经典运动方程，并建立了准经典与量子力学蛇形态之间的对应关系。基于轨迹分析，我们设计了雕刻衬底以实现各种“光学器件”，如会聚透镜或准直器，并且进一步提出一种仅通过衬底图案化就能实现谷霍尔效应的装置，无需任何外部场，可用于谷电子学应用。最后，我们讨论了预测的应变/赝电磁场图案如何能通过典型衬底在实验中得以维持，并推广到其他二维材料。
